Turmeric (Curcuma domestica) and milk-derived by-products are increasingly explored as natural, antibiotic-free feed additives for rabbit production, yet evidence on their combined use at graded protein-source levels remains limited, particularly for New Zealand White rabbits reared under smallholder tropical conditions. This study evaluated the effect of a fixed level of turmeric flour (0.4%) combined with three levels of skim milk powder (0%, 5%, and 10%) on the growth performance, feed consumption, feed conversion ratio (FCR), and protein efficiency ratio (PER) of growing New Zealand White rabbits. A Completely Randomized Design (CRD) was used with three dietary treatments — P0 (0.4% turmeric flour, 0% skim milk powder), P1 (0.4% turmeric flour, 5% skim milk powder), and P2 (0.4% turmeric flour, 10% skim milk powder) — each replicated six times, for a six-week observation period following a two-week adaptation. Body weight gain was highest in P2 (21.30 ± 4.94 g/rabbit/day) compared with P1 (16.70 ± 3.78) and P0 (14.00 ± 2.37) (p < 0.05). Feed consumption was also highest in P2 (96.11 ± 12.66 g/rabbit/day) relative to P1 (76.72 ± 7.84) and P0 (73.54 ± 13.42) (p < 0.01). FCR (4.60–5.30) and PER (0.97–1.10) did not differ significantly among treatments (p > 0.05), although numerically the most favorable values were recorded in P2 and P1, respectively. These findings indicate that combining turmeric flour with a higher level of skim milk powder enhances growth rate and feed intake without compromising feed efficiency, supporting its potential as a practical, natural growth-promoting strategy in rabbit farming. Carcass composition was not assessed in this trial; further studies incorporating carcass traits, nutrient digestibility, and dose–response evaluation are recommended.